The study reported in this paper measures differences in profitability between conservation farming (CF) practices and conventional agriculture by comparing the value of differential output with the differential input costs. The main objective is to address and fill several important knowledge gaps by investigating three key features of conservation farming in Zambia: 1) the process by which CF originated and spread; 2) the scale of CF adoption across household groups and regions; and 3) the impact of CF on crop output, input use, cost of production and farm income.